Fungicidal method and composition containing phosphonothionothiolate derivatives



United States Patent U.S. Cl. 424-210 3 Claims ABSTRACT OF THE DISCLOSURE Plant fungicide compositions that contain phosphonothionothiolate derivatives. A method of controlling plant fungi and rice blast disease by applying this composition to the plant surface.

The objective of the present invention is to offer an excellent fungicide with which to fight plant diseases. The organic phosphorus compounds according to this invention are highly effective to prevent plant diseases caused by fungi, such as rice blast; sheath blight; leaf rust of barley; anthracnose of melon; black spot of pear. Particularly their effect against rice blast is superior and, moreover, this effect is residual.

Another objective of this invention is to offer a fungicide which possesses low toxicity to mammalia and plants.

The present invention relates to a fungicide characterized by containing one or more of Organic phosphorates as expressed by the following general formula:

X: sulphur or oxygen where R lower alkyl radical.

R hydrogen or cyano radical or COOR radical.

R lower alkyl radical.

R and R may be the same or different and are lower alkyl radical with 1--3 carbon atoms.

The fungicide of the present invention can be easily synthesized by the following reactions.

For the synthesis of the following general formula:

R S H (where R R are the same as above), the following reaction is employed:

P-S-Me Y-(J- Q I Y 3,472,932 Patented Oct. 14, 1969 For the synthesis of the following general formula:

R10 ICI) H P s Q R1 (where R R are the same as above), the following reaction is employed:

(where R R Me and Y are the same as above.)

For example, O-alkyl-S-benzylphenylphosphonothiolate of the following general formula:

can be synthesized by condensation of potassium O-alkylphenylphosphonothionate with benzylchloride as follows:

(where R is the same as above.)

And 0 alkyl-S-(alkoxycarbonyl) (phenyl)methylphenylphosphonothionothiolate as expressed by the general formula:

(DOOR;

(where R R are the same as above), can be synthesized through reaction between sodium O-alkylphenylphosphonothionothionate and u-halogenophenylacetic acid alkylester as follows:

COORa PSC Na-Y o 0 0 R; (where R R and Y are the same as above.)

The typical organic phosphorate which constitute the effective ingredient of the fungicide according to the present invention are as follows:

O-i-propyl S-(cyano) (phenyl)methylphenylthionothiolate,

O-methyl S- (methoxycarbonyl) (phenyl) methylphenylphosphonothiolate,

O-methyl S- (ethoxycarbonyl) (phenyl) methylphenylphosphonothiolate,

O-ethyl S-(ethoxycarbonyl) (phenyl)methylphenylphosphonothionothiolate,

O-n-propyl S-(ethoxycarbonyl) (phenyl)methylphenylphosphonothiolate,

O-i-propyl S- (ethoxycarbonyl) (phenyl) methylphenylphosphonothiolate.

To be used as a fungicide, the organic phosphor-ates in this invention are evenly blended with inert carriers such as talc, clay, kieselguhr and vermiculite in accordance with the routine process; then they may be applied as a dust after being crushed to, say, 300 mesh; or may be mixed with an adjuvant such as a surface active agent or a suspension agent and applied as wettable powder to be diluted with water. Or they may be dissolved in a inert solvent such as toluene or xylene, mixed with some appropriate emulsifying agent; and then applied as emulsion. Or, depending on the necessity, they may be employed in combination with some other fungicide, insecticide, herbicide or fertilizer.

The following illustrates some typical cases of testing the fungicide of this invention.

Test l.Pot test for rice blast prevention The test was carried out as follows.

Rice plant (variety: Aichiasahi, 4-5 leaves stage) cultivated in 15 cm. pot was treated with a water-diluted emulsion of the concentration specified in Table 1, said emulsion being a mixture having the following composition:

40 parts of text compound as listed in Table 1, 50 parts of xylene; and 3 parts of sodiumalkylbenzenesulfonate and 7 parts of polyoxyethylensorbitanmono-oleate as surface active agents. Twenty-four hours after the rice plant was sprayed with said emulsion, a spores suspension of Piricularia oryzae (containing 12-l6 spores in X150 field of microscope) was sprayed on said rice plant for inoculation of spores. Said plant was held for 48 hours at a temperature of 23-28 C. and in dew-wet condition. Thereafter it Was left within a green house maintained at about 25 C. After 7 days, the disease rate per leaf was investigated, the average disease rate per leaf was determined and the protective value was calculated.

The investigation was conducted with two upper leaves for each plant. One pot held 20 plants and two pots were tested every time. The investigation averaged about 80 leaves. To determine the disease rate per leaf, the affected degree of the investigated leaves (two upper leaves for each plant) was graded in five: (healthy), 1 (several diseased spots), 2 (spots: -10), 3 (numerous spots), and 4 (affected area: over 80%). The average disease rate per leaf was calculated according to the following formula:

Average disease rate per leaf:

(Where n number of leaves rated 0; 11 number of leaves rated 1; n number of leaves rated 2; n number of leaves rated 3; n number of leaves rated 4; n +n +n +n +ng total of investigated leaves.)

Protective value= X 100 4 (where a: average disease'rate per leaf of control; b: that of fungicide-treated plant.)

TABLE l.RESULTS OF POT TEST FOR RICE BLAST PREVENTION Average Concendisease Protectration, rate per tive Test compounds p.p.m. leai value Damage O-ethyl S-(benzyl) phenyl- 500 0. 33 78 N egativc.

phosphonothionothiolate. Oethyl S-(benzyl) phenyl- 500 0. 1O 93 Do.

phosphonothiolate. O-n-propyl S-(benzyl) 500 0. 49 67 Do.

phenylphosphonothionothiolate. O-n-propyl S-(benzyl) 500 0. 18 88 Do.

phenylphosphonothiolate. Control 1. 50 0 Do.

Test 2.Pot test for rice blast prevention as compared with mercury compounds The test was performed similarly to Test 1 with the same preparation of fungicide as in Example 1.

TABLE 2.-RESULTS OF POT TEST FOR RICE BLAST PRE- VENTION AS COMPARED )WITH MERCURY COMPOUNDS Average Concendisease Protectration, rate per tive Test compounds p.p.m. 1e value Damage O-methyl S-(benzyl) 500 0.16 91 Negative.

phenylphosphonothid nothiolate. Control PMI (phenyl- 1 2O 0. 21 88 Do.

mercurie iodide). Control 1.80 0 Do.

1 As Hg.

Test 3.Pot test for rice blast prevention similarly to Example 1 Three pots were tested every time. Fungicide was prepared similarly to Test 1.

TABLE 3.RESULTS OF POT TEST IN TEST 3 FOR RICE BLAST PREVENTION Test 4.-Pot test for rice blast prevention The test was performed in the same way as in Test 1, but using a fungicide prepared by mixing 40 parts of test compound, 45 parts of xylene and 5 parts of sodiumalkylbenzenesulphonate and 10 parts of polyoxyethylensorbitanmono-oleate as surface active agents and diluting the obtained mixture to the specified concentration.

The results are given in Table 4.

TABLE 4.RESULTS OF POT TEST IN TEST 4 Average Conoendisease Protectration, rate per tive Test compounds p.p.m. 1e value Damage O-methyl S-(ethoxycar- 1,000 0.15 95 Negative.

bonyl) (phenyDmethylphenylphosphonothioa e. Control (0,0-diethyl S- 1, 000 0. 94 72 Positive.

benzylphosphonothit late).

Do 500 1. 29 (51 Positivenegative Control 3. 30 0 Negative.

Test 5.-Pot test for rice blast prevention Similar test to Test 1, with the results obtained as shown in Table 5.

5 (total withering). The average disease rate per plant was calculated as follows: Average disease rate per plant:

TABLE 5.RESULTS OF POT TEST FOR RICE BLAST PREVENTION IN TEST 5 5 "o'+"1'+ 2'+"s'+ 4"+"s' Av ra e (where n number of diseased leaves rated 0 per plant; g i eg Pro t eg n number of diseased leaves rated 1 per plant; n Test compounds p.p.m. 1e value Damage number of diseased leaves rated 2 per plant; n number e o ethyls (benzyl)phenyl 500 0 100 Negative. of diseased leaves rated 3 per plant, n number of phesphonothiolate. diseased leaves 4 per plant; 12 number of diseased 8: 33; leaves 5 per plant; n ':|n '+n '+n '+n :+n denotes ts; 7 5 33. the total number 1nvest1gated, 1.e., equal to 60 plants.)

' TABLE 9.-RESULTS 0F FIELD TEST USING RICE 1 SEEDLING OF RICE BLAST Test 6.-Pot test for nce blast prevention A verage Similar test to Test 1, with the results obtamed as q dlsease t tration, rate per two Table 6. Test compounds p.p.m. leaf value Damage TABLE 6-RESULTs 0F POT TEST IN TEST 6 O-methyl S-(ethoxyoar- 1,000 2.08 42 Negative.

Average bonyl) (phenyDmethylg tq dgsease tt glggnylphosphonothw 1'2. 1011, I3. 8 per 1V6 Test compounds p.p.m. leaf value Damage ggggb ggggg g 1'000 37 O-methylS-(benzyl) 1,000 0.22 84 Negative. gggq glgg p v p p Control (0,0-diethyl S- 1,000 2.32 36 Positivelate. (benzyl) phosphononegative- 500 0. 45 67 D 0. thiolate) Control 35 0 130- Don" 500 3 25 10 Contr 3.60 0 Negative- Test 7.-Pot test for rice blast prevention In the followin the resen invention illusr S1m1lar test to Test 1, with the fung1c1de prepared In by examples of applifationp t is t ated the same way as Test 4. The results obtained are given in Table 7. Example 1 TABLE 7.RESULTS OF POT TEST IN TEST 7 Emulsion is obtained by mixing the following:

Average Parts Concendisease Proteotration, rate per tive O-methyl S-(benzyl)phenylphosphonoth1onoth1olate 30 Test compounds p.p.m. leaf value Da age S l (Xylene) 50 O-ethylS-(ethoxycarbonyl) 500 o 100 Negative. Solvent (acetone) 10 (phenynmethylphenw Surfactant (sodiurnalkyl-benzenesulphonate) 3 phosphonothiolate.

Do 0.11 a: Do. 40 Surfactant (p01yoxyethylenesorbltanmono-oleate) 7 o. 11 9 Do. p.33 8g B The emulsion is diluted with water for use.

Example 2 Test 8.--Pot test on residual effect of fungicide for nce Emulsion is obtained by mixing the following:

blast preventron Parts Test was carried out srrmlarly to Test l, wh ch was O-ethyl S-(benzyl)phenylphosphonothiolate executed M hours and 48 hours after spraymg W th 1 Solvent (xylene) 30 suspension of Piricularia oryzae. The fung1c1de prepara- Surfactant (sodiumalkylbenzenesulphonate) 6 tion was the same as Test 4. Surfactant (polyoxyethylenesorbitanmono-oleate 14 TABLE 8.-RESULTS OF POT TEST ON RESIDUAL EFFECT OF FUNGICIDE Inocu- Average Concenlation, 'sease Protee tration, hours rate per tive Test compounds ppm. later value Damage th 13- th carb n 1 250 24 0.02 99 N t 0 D (e oxy o y) 250 48 0.36 85 izvg 0.15 94 Do. 0.36 85 Do. 2. 43 0 Do.

Test 9.Field test using rice seedling of rice blast The test was carried out as follows. Exam 1e 3 Seed bed 70x90 cm. (dense sown, N-nch) were pre- P pared and sown with rice seeds (variety: A1ch1asah1). Beginning on T 10th y Of SOWlIlg, the P was P Y Emulsion is obtained by mixing the following: with the fungicide three times (150 cc./p1ot) every seven days. Thereafter, 30 plants were random-sampled from each plot on the 7th day. The disease rate per plant was Parts investigated; the average disease rate per plant and the protective value were calculated. In this investigation, two plots were tested for each treatment.

The disease rate per plant was graded in six degrees: 0 (healthy), 1 (several diseased spots), 2 (numerous diseased spots), 3 (some top leaves withering on account O-methyl S-(cyano) (phenyl)methylphenylphosphonothionothiolate 20 Solvent (xylene) 60 Surfactant (polyoxyethylenesorbitanmono-oleate) 15 Surfactant (sodiumalkylbenzenesulphonate) 5 Example Wettable powder is obtained by mixing and crushing the following:

Parts O-ethyl S-(benzyl)phenylphosphonothiolate 30 Carrier (clay) 65 Surfactant (polyoxyethylenenonylphenolether) 4 Suspension agent (sodiumligninsulphonate) 1 This wettable powder is diluted with water for use.

Example 6 Wettable powder is obtained by mixing and crushing the following:

Parts O-ethyl S-(cyano) (phenyl)methylphenylphosphonothionothiolate 40 Carrier (talc) 55 Surfactant (polyoxyethylenenonylphenolether) 4 Suspension agent (sodiumligninsulphonate) 1 This wettable powder is diluted with water for use.

Example 7 Wettable powder is obtained by mixing and crushing the following:

Parts O-n-propyl S- (ethoxycarbonyl) (phenyl)methylphenylphosphonothiolate 40 Carrier (bentonite) 5S Surfactant (sodiumalkylbenzenesulphonate) 4 Suspension agent (sodiumligninsulphonate) 1 This wettable powder is diluted with water for use.

Example 8 Dust is obtained by evenly mixing and crushing the following:

This dust is applied as it is.

Example 9 Dust is obtained by evenly mixing, crushing and sifting the following through 300 mesh sieve:

, 7 Parts O-ethyl S-(cyano) (phenyl methylphenylphosphonothiolate 3 Carrier (clay) 30 Carrier (talc) 67 This dust is used as it is.

Example 10 Dust is obtained by evenly mixing and crushing the following:

Parts 0 ethyl S (ethoxycarbonyl) (phenyl}methylphenylphosphonothiolate Carrier (talc) 97 This dust is used as it is.

What is claimed is:

1. A plant fungicide composition comprising a fungicidally effective amount of a compound having the formula in which R represents a lower alkyl, having 1 to 3 carbon atoms, X is selected from the group consisting of sulphur and oxygen, R is selected from the group consisting of cyano, and COOR in which R, is a lower alkyl having 1 to 3 carbon atoms and an inert carrier.

2. The method of inhibiting the growth of plant fungi on plants which comprises the step of applying to the plant fungi on said plant a fungicidally effective amount of the composition of claim 1.

3. The method of claim 2 wherein said plant is rice and said plant fungi are rice blast fungi.

References Cited UNITED STATES PATENTS 2,992,265 7/1961 Schrader 16730 XR 3,013,047 12/1961 Schrader 16730 XR 3,185,723 5/1965 Floyd 260-941 ALBERT T. MEYERS, Primary Examiner D. R. MAHANAND, Assistant Examiner US. Cl. X.R. 

